Three-spine stickleback

Sticklebacks have adapted themselves to their surroundings in the same way as Arctic charr, as 2 varieties of stickleback have evolved. One variety stays in the vegetation belt at a depth of 25-30 metres, where a suitable habitat is found, while the other frequents shallower areas amongst the lava stones. Sticklebacks are by far the most common fish in the lake; their number estimated at 85 million.